Comment 45 for bug 984785

> oh yes! checked the code and then again lost my memory :).
No problem. Happens :)

In short: I'm pretty sure now, that lightdm is creating these files.

In long:

I modified my ps-log.sh a bit, ran it several times and saw, that lightdm sometimes appeared in the log right before the file was created and sometimes right after it. This implies, that lightdm creates the file very fast after starting.

Also tried starting lightdm. Didn't work (maybe would have, if I had tried with --test-mode from a tty):
$ lightdm
Only root can run Light Display Manager. To run as a regular user for testing run with the --test-mode flag.
$ lightdm --test-mode
Running inside an X server requires Xephyr to be installed but it cannot be found. Please install it or update your PATH environment variable.

Logged whole command line of lightdm as started on shutdown:
lightdm --session-child 12 19

--session-child is not documented in the man page.

Tried this command in a running session, but no .goutputstream-* file was created (neither in current working directory, nor in ~):
$ lightdm --session-child 12 19
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Error reading from daemon: Bad file descriptor
Failed to start PAM: System error

Then I tried logging with inotifywait and lsof (again, but modified script). This is a part of the log file:
lightdm 1348 a 9w REG 8,6 46 304928 /home/a/.goutputstream-YJRHEW

-> It's really lightdm.

2 scripts + logfiles attached.